Apparatus for applying a film of glue to box blanks and the like



R. c. TOWER 3,353,517

APPARATUS FOR APPLYING A FILM OF GLUE TO BOX BLANKS AND THE LIKE Nov. 21, 1967 Sheets-Shee Filed Jan. 14, 1965 INVENTOR.

RAYMOND c. TOWER ATTORNEYS Nov. 21, 1967 R. c. TOWER 3353,51?

APPARATUS FOR APPLYING A FILM OF GLUE TO BOX BLANKS AND THE LIKE Filed Jan. 14, 1965 2 Sheets-Sheet 2 INVENTOR. RAYMOND C. TOWER WW/2:2 w

ATTORNEYS United States Patent Ofifice 3,353,517 APPARATUS FOR APPLYING A FILM F GLUE T0 BOX BLANKS AND THE LIKE Raymond C. Tower, Spencer, Mass., assignor to M. B. Clatf & Sons, Inc., Brockton, Mass., a corporation of Massachusetts Filed Jan. 14, 1965, Ser. No. 425,559

Claims. (Cl. 118-261) ABSTRACT OF THE DISCLOSURE An improvement in the scraper an roll elements of glue-applying apparatus by which a thin film of glue is applied to material such as box blanks. A scraper block is disclosed having a gradually converging entrance region' into which an excess of glue is crowded of the advancing roll, a channel through which excess glue may be drained off and foreign matter flushed away, and' a region closely spaced from the roll surface to permit passage of a thin film of glue on the roll surface. The surface of the roll has oblique channels to induce flow of excess glue in a preferred direction along the channel in the scraper block.

, The present invention relates to improvements in gluing apparatus for applying adhesive to predetermined areas of box blanks, in the manufacturing of paper boxes and cartons.

In the usual box setting-up machine, boxes are assembled from flat blanks in a series of steps which involve gluing, folding and pressing operations. In machines in which the blanks are advanced past the various operating instrumentalities, the gluing operation is carried out by contacting the moving blank with a roll, the surface of which is coated with a thin film of glue. The glue roll is rotated at a peripheral speed corresponding to the rate of advance of the blank, with the lower portion of the roll immersed in a tank or trough of glue.

To maintain the desired film thickness of glue on th: roll for proper adhesion when the blank is folded, a scraper is mounted in closely-spaced adjustable relation to the roll, so as to intercept and remove excess glue prior to contact of'jthe coated roll with the surface of the ad-- vancing blank.

1 In the operation of such devices, the gap between the scraper blade and the roll tends to become clogged with fibers and bits of cardboard carried into the glue from the blanks. Any solid matter caught at the edge of the scraper blade affects the thickness of the glue film at that region, and a build-up of fibers and bits of paper can quickly result in an inadequate amount of glue for the adhesive bond. As a consequence, conventional roll and scraper blade gluing devices require frequent attention and cleaning in order to operate properly in applying a uniform film of glue in the proper amount to the surface of the blank.

The present invention has as its object to provide a blank, in the area to be adhesively secured, maybe of 3,353,517 Patented Nov. 21, 1967 optimum thickness for strength of bond consistent with speed of setting, when the box blank is formed into final shape during the steps subsequent to gluing.

The several features of the invention, wherein the means for controlling the glue film thickness on the roll is maintained free of foreign matter, will be apparent from the description which follows, taken in conjunction with the accompanying drawings in which:

FIG. 1 is a top plan view of a gluing mechanism embodying the invention, showing glue roll, glue pot and adjusting means in control of film thickness.

FIG. 2 is a view in side elevation, partly in section, of the apparatus shown in FIG. 1 and taken on the line 2-2 of said figure.

FIG. 3 is a detail sectional view taken on the line 3-3 of FIG. 2, showing details of the adjustable mounting for the scraper element.

FIG. 4 is an enlarged detail in elevation, showing a portion of the glue roll and scraper block, and

FIG. 5 is a sectional detail of the parts shown in FIG. 4 taken on the line 5-5 of said figure.

Referring to FIG. 2, the glue roll 12 is mounted on a power-driven shaft 14 for rotation at a rate such that the peripheral speed of the roll corresponds to the linear speed of advance of the box blank 16 between the top of the glue roll and a pressure or hold-down roll 18. In a typical setting-up machine, gluing units are positioned on each side of the path of blank advance so as to apply glue to the underside of predetermined marginal portions of the blanks, such as the end wings.

The lower portion of the glue roll 12 passes through the glue 20 within the conventional glue pot 22 hung on supports 24. As a result of the'rotation of the roll in counter-clockwise direction as viewed in FIG. 2, the glue is carried upwardly on the periphery of the roll in a'relatively thick layer or coating 26. To limit the amount of glue applied to the underside of the blank which contacts the glue roll as the blank is fed past, most of the glue on the roll as it is carried upwardly in the'layer 26 must be scraped or stripped away, leaving a relatively thin film to be transferred to the blank, sutficient to give a strong, quick-setting bond when the blank is formed into a box by instrumentalities to which the blank is advanced following the gluing.

As has previously been indicated, the conventional scraper blade or knife that is employed to scrape the glue roll of all but the desired thin film of glue, tends to become clogged, in the gap between the edge of the scraper and the roll, with fibers and bits of paper which fall from the passing blanks into the glue pot and become suspended in the liquid. To provide a means of elfectively controlling the thickness of the glue film carried into contact with the box blank and at the same time" side wall 34 which overhangs one edge of the roll. A-

plate 36 is mounted on the other end of the block so as to form a side wall that overhangs the other edge of the roll 12, there being sufi'icient clearance to permit rotation of the roll between thewalls 34 and 36.

The block is mounted on a support 42 secured to short cross shaft 44 in the top portion. of the glue pot. The

mounting includes a connector piece 46 secured at one end to the support 42 and at its other end to the block' 32. To permit slight transverse tilting adjustments of the that the gap may be of uniform thickness, one of the abutting surfaces between support 42 and connector piece 46 has a slight transverse curvature, as shown in the sectional detail, FIG. 3. By suitable adjustment of the machine screws 48 which secure the parts, the connector piece 46 may be tilted one way or the other and thereby rock the scraper block, after which both screws are tightened uniformly to secure the setting.

As shown in FIG. 4, the block has a generally oblique face which is disposed in proximity to and extending along a portion of the periphery of the glue roll in spaced relation thereto. This oblique face of the block is advantageously described in terms of zones or regions, each of which contributes to the effectiveness of the operation in maintaining a uniform thickness of the glue film that is left on the roll following the action of the scraper block. The first region, into which the upwardly-rotating roll carries the relatively thick coating 26 of glue, is defined by a surface 54 which converges inwardly at a slight angle to the roll periphery or, more strictly, to a tangent to said periphery. The glue crowds into this converging region, as indicated at 56, and a pressure build-up results as the glue is carried along toward the narrow end of this converging entrance region 54.

The glue next enters a region defined by an enlargement or channel 60 extending transversely of the block the full width of. the roll 12. This channel serves as a lateral escape passage for the excess of glue that has been carried along as a result of the build-up within the converging region 54, the glue flowing along the passage to the right, as viewed in FIG. 5, toward the wall 34 and through the enlarged opening62 where it discharges into the glue pot. For the gluing unit on the other side of the blank, the arrangement of the parts would be the reverse of that shown in FIG; 5, with the wall 34 at-the left and the flow of glue taking .place from right to left in channel 60 into enlarged opening'62 in wall 34 at the left side of roll 12 and thence into the glue pot.

This transverse flow of excess glue is. effective to sweep away any bits of scrap or fibers that would otherwise tend to collect at the narrow gap between the portion 64 of the block 32 and roll 12 in the zone or region that determines the final thickness of the glue film as it leaves the scraper block and is carried into contact with the box blank.

To enhance the lateral flushing action of the excess glue prior to passage into the narrow gap in the exit region of the scraper block, the periphery of the roll may be provided with a plurality of spaced open channels 66 that extend obliquely across the surface of theroll. These channels are disposed at an angle that complements or enhances the flow of excess glue in the channel 60 in toward the discharge outlet 62 in wall 34. These channels also provide at frequent intervals, extra clearance for the dislodging of any particles that should be caught at the exit gap between scraper. and roll, permitting said particles readily to be flushed or carriedaway to leave the film-controlling gap. unobstructed by foreign matter. It will be observed in FIG. 2 that these channels are not employed in the region of the roll periphery which contacts the box blank, in order not to transfer to the blank excessive amounts of glue in localized areas. Appropriate coordination of the glue roll drive with the blank feed makes it possible for the portions of the box blank that are to receive the glue to come into contact only with the smooth surface of the glue roll. The thickness of the glue film as it leaves the exit gap between scraper and roll is controlled by means of arm 72 secured to shaft 44 on which the scraper block 32 is carried. A hand wheel 74 having a threaded shank received in boss 76 is provided with nuts 78 below and a compression spring 80 above the arm so that rotation of the hand wheel provides a precise means of rocking shaft 44 and hence adjusting the clearance between surface 64 on the scraper and the adjacent surface of the roll.

It will be apparent from the foregoing description and accompanying drawings that the glue roll and scraper block embody novel and useful constructions and configurations which permit operation over extended periods with a minimum of attention, as a consequence of the positive and automatic flushing action that occurs in the immediate vicinity of the narrow gap which determines the final film thickness on the roll. In particular, the converging entrance region with its pressure build-up enables the transverse channel 60 to receive and provide lateral flow for a substantial quantity of excess glue to flush the final film-controlling gap between scraper and roll. The provision of a few oblique channels in the roll surface adds a further clearing and flushing action in the critical gap region.

I claim as my invention:

1. A gluing mechanism for applying a glue film of predetermined thickness to box blanks and the like comprising a glue pot, a glue roll rotatably mounted in said pot, and a scraper element mounted in adjustably-spaced relation to the surface of the roll in the region of roll advance from the glue toward the point of application to the work, said scraper element comprising a block having an entrance portion converging toward the roll periphery, an exit portion in closely-spaced relation to the roll periphery for passage of a thin film of glue therebetween, and a channel extending transversely of the block intermediate the converging and the exit portions of the block and open toward the roll surface for conveying excess glue laterally of the block and roll and for dischargingsaidexcess into the pot, the periphery of the glue roll having a plurality of spaced open channels extending obliquely across the surface of the roll to cause the flow of excess gluein the channel in the scraper block to take place primarily in one direction. I

2. A gluing mechanism for applying a glue film of predetermined thickness to box blanks and the like comprising a glue pot, a glue roll rotatably mounted in said pot, and a scraper element mounted in adjustably-spaced relation to the surface of the roll in the region of roll advance from the glue toward the point of application to the work, said scraper comprising a block extending along a portion of the periphery of the roll and having side walls alongside said roll, said block having an oblique entrance portion converging toward the roll periphery, an exit portion in closely-spaced relation to the roll periphery for passage of a thin film of glue therebetween, and a channel extending transversely of the block substantially the width of the roll periphery intermediate the converging and the exit portions of the block and open to the roll surface for conveying excess glue laterally of the block and roll, one of said walls having a passage aligned with said channel for discharging said excess glue into the glue pot.

3. A gluing mechanism for applying a glue film of predetermined thickness to box blanks and the like comprising a glue pot, a glue roll rotatably mounted in said pot, and a scraper element mounted in adjustably-spaced relation to the surface of the roll in theregion of roll advance from the glue toward the point of application to the work, said scraper comprising a block extending along a portion ofthe periphery of the roll and having side walls alongside said roll, said block having an oblique entrance portion converging toward the roll periphery, an exit .portion in closely-spaced relation to the roll periphery for passage of a thin film of glue therebetween, and a channel extending transversely. of the block substantially the width of the roll periphery intermediate the converging and the exit portions of the block and open to the roll surface for conveying excess glue laterally of the block and roll, one of said walls having a passage aligned with said channel for discharging said excess glue into the glue pot, the periphery of the glue roll having a plurality of spaced open channels extending obliquely across the surface of the rollin a direction complementing the flushing of excess glue in the channel in the block laterally toward the discharge passage.

4. Gluing mechanism according to claim 1, including a side wall on the block alongside said roll on the side toward which the excess glue flows in the channel in the block under the influence of the oblique channels in the roll periphery, said side wall having a passage for the discharge of excess glue from the channel into the glue pot.

5. A gluing mechanism for applying a glue film of predetermined thickness to box blanks and the like comprising a glue pot, a glue =roll rotatably mounted in said pot, and a scraper element mounted in adjustably-spaced relation to the surface of the roll in the region of roll advance from the glue toward the point of application to the work, said scraper element comprising a block having an entrance portion converging inwardly toward the roll periphery outwardly of and at a slight angle to a tangent touching said glue roll closely adjacent the inner most part of said converging portion to form a gradually converging passage whose dimension peripherally of the roll is substantially greater than the spacing between roll and block throughout said converging region, an exit portion in closely-spaced relation to the roll periphery for passage of a thin film of glue therebetween, and a channel extending transversely of the block intermediate the converging and the exit portions of the block and open toward the roll surface for conveying excess glue laterally of the block and roll and for discharging said excess into the pot.

References Cited UNITED STATES PATENTS 1,045,222 11/1912 Twomley 118261 X 1,080,959 12/1913 Eaton 11826-1 X 1,127,538 2/1915 Staude 118-261 X CHARLES A. WILLMUTH, Primary Examiner.

L. G. MACHLIN, Assistant Examiner. 

1. A GLUING MECHANISM FOR APPLYING A GLUE FILM OF PREDETERMINED THICKNESS TO BOX BLANKS AND THE LIKE COMPRISING A GLUE POT, A GLUE ROLL ROTATABLY MOUNTED IN SAID POT, AND A SCRAPER ELEMENT MOUNTED IN ADJUSTABLY-SPACED RELATION TO THE SURFACE OF THE ROLL IN THE REGION OF ROLL ADVANCE FROM THE GLUE TOWARD THE POINT OF APPLICATION TO THE WORK, SAID SCRAPER ELEMENT COMPRISING A BLOCK HAVING AN ENTRANCE PORTION CONVERGING TOWARD THE ROLL PERIPHERY, AN EXIT PORTION IN CLOSELY-SPACED RELATION TO THE ROLL PERIPHERY FOR PASSAGE OF A THIN FILM OF GLUE THEREBETWEEN, AND A CHANNEL EXTENDING TRANSVERSELY OF THE BLOCK INTERMEDIATE THE CONVERGING AND THE EXIT PORTIONS OF THE BLOCK AND OPEN TOWARD THE ROLL SURFACE FOR CONVEYING EXCESS GLUE LATERALLY OF THE BLOCK AND ROLL AND FOR DISCHARGING SAID EXCESS INTO THE POT, THE PERIPHERY OF THE GLUE ROLL HAVING A PLURALITY OF SPACED OPEN CHANNELS EXTENDING OBLIQUELY ACROSS THE SURFACE OF THE ROLL TO CAUSE THE FLOW OF EXCESS GLUE IN THE CHANNEL IN THE SCRAPER BLOCK TO TAKE PLACE PRIMARILY IN ONE DIRECTION. 